• Journal of Chest Surgery
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• v.27 no.9
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• pp.785-792
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• 1994

In this study, the authors analyzed the prognostic value of four clinical variables[age and sex of patients, association with myasthenia gravis and clinical stage] and histological type in 30 consecutive patients with thymoma, histologically classified as cortical[10],medullary[5] and mixed[15]type according to Marino and Muller-Hermelink classification. There were significant differences between the histological types in the frequency of the different tumor stages and myasthenia gravis and prognosis.Most of the cortical thymomas were at stage III and all of the medullary and most of the mixed tumors at stage I or II.Myasthenia gravis occurred more commonly in patients with cortical[30%] and mixed thymoma[60%] than in patients with medullary thymoma[10%]. Follow-up was conducted in 30 patients,with follow-up range from 3 months to 120 months[mean,47.3months]. 5 year actuarial survival was 100% for medullary thymoma, 73% for mixed thymoma, and 47% for cortical thymoma.The overall survival curve shows that 87.6% of the patients are alive at 2 years and 72.8% at 5 years. And 7 patients was dead during follow-up periods.By Kaplan-Meier technique, we found that the patients who had myasthenia gravis had better prognosis[P<0.05]. Medullary thymoma is a comparatively rare, benign tumor, and usually not associated with myasthenia gravis. Cortical thymoma must be regarded as malignant. Mixed thymoma is intermediate in its behavior between medullary and cortical thymoma. But these tumors should be considered potentially malignant despite of presence as stage I of II disease. Also, the patients with stageI,II had good prognosis and the patients with total resection had good prognosis[P<0.05].

• The Korean Journal of Cytopathology
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• v.4 no.1
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• pp.16-24
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• 1993

The fine needle aspiration (FNA) cytologic findings in 16 cases of histologically confirmed thymoma are reported. The aspirates were obtained under fluoroscopic guidance. The cytologic diagnoses were inadequate sample in one case, thymoma in 12(75%), small cell carcinoma or thymoma in 1, benign mesenchymal tumor in 1, and germ cell tumor in one. The cytologic features were detailed according to the constituent epithelial cell type, and into 4 small of epithelial cells and lymphocytes. Fifteen cases were classified into 4 small epithelial cell type, 6 intermediate epithelial cell type, 1 large epithelial cell type, 1 large pleomorphic epithelial cell type, and 3 spindle-shaped epithelial ceil type. Cytologic differential diagnosis was discussed, and the important criteria for the cytologic diagnosis of thymoma were reviewed. This review leads us to think that nonoperative cytologic approaches in the diagnosis of the thymoma are possible, and that correct cytologic diagnosis of thymoma with FNAs can easily be made, if adequate samples are obtained However the invasiveness and histologic type could not be predicted by cytological features only. Knowing various cytologic and histologic features of thymoma will be helpful for the diagnosis of thymoma and the differential diagnosis of modiastinal tumors.

• The Korean Journal of Cytopathology
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• v.11 no.1
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• pp.41-45
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• 2000

Thymoma is the most common anterior mediastinal tumor in adults. Rarely, it is presented as the anterior neck mass, commonly located in the anterolateral aspect of the neck or adjacent to the thyroid. We experienced two cases of fine needle aspiration cytology of thymoma, mimicking thyroid mass. The first case was an ectopoic cervical thymoma in a 31-year-old female. The fine needle aspiration cytology was misinterpreted as reactive hyperplasia of lymph node. But the histologic diagnosis was thymoma, predominantly lymphocytic type. The second case was an invasive thymoma in a 66-year-old female, who complained a large anterior neck mass. The fine needle aspiration cytology revealed biphasic population of some clusters of epithelial cells and scattered lymphocytes. The cytologic diagnosis was thymoma and was confirmed as invasive thymoma after the biopsy. Therefore, when the cytologic feature of anterior neck mass shows the both lymphocyte and epithelial component, the differential diagnosis should Include the possibility of thymoma.

• The Korean Journal of Cytopathology
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• v.2 no.1
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• pp.36-42
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• 1991

We report 4 cases of malignant thymoma which were composed of 2 cases of invasive thymoma and 2 cases of thymic carcinoma. The cytologic findings of invasive thymoma were similar to those of benign thymoma. The distinctive cytologic features of thymic carcinoma were necrotic background, irregular clusters and individually scattered arrangement of anaplastic epithelial cells, and some scattered mature small lymphocytes. These findings may be found in the Hodgkin's lymphoma, seminoma, and metastatic squamous ceil carcinoma, undifferentiated carcinoma, and large ceil carcinoma of the lung. But, the feature of irregular clustering of anaplastic epithelial cell haying scanty cytoplasm was different from Hodgkin's lymphoma and seminoma. Clinical and radiologic findings as well as cytologic finding were helpful in differential diagnosis of thymic carcinoma from metastatic carcinoma.

• Journal of Chest Surgery
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• v.27 no.4
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• pp.303-309
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• 1994

Eighteen patients with thymoma have undergone surgical treatment at Pusan National university Hospital from 1983 to 1993. The mean age of the patients was 47.3$\pm$13.3 years old and male to female ratio was 1.6 : 1. Eleven of the patients[61.1%] with thymoma had myasthenia gravis; 12 cases[66.7%] were encapsulated and 6[33.3%] invasive. Operation was complete resection in 14[77.8%] of the patients, partial resection with residual tumor in 3[16.7%], and simple biopsy in one[5.5%]. Adjuvant radiotherapy was administered in 5 of 6 invasive thymoma. Postoperatively one patient died for excessive bleeding and sepsis. A tumor relapse was observed in one patient who had invasive thymoma and underwent partial resection followed by postoperative radiotherapy. The overall 5-year survival rate was 88.2$\pm$ 7. 9%.The presence of myasthenia gravis is not considered as an adverse factor for survival but it contributes to early discovery of associated thymoma.

• Journal of Chest Surgery
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• v.50 no.1
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• pp.68-70
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• 2017

The actual incidence of multiple thymoma is unknown and rarely reported because it remains controversial whether the cases represent a disease of multicentric origin or a disease resulting from intrathymic metastasis. In this case, a patient underwent total thymectomy for multiple thymoma with myasthenia gravis via bilateral video-assisted thoracic surgery. A well-encapsulated multinodular cystic mass, measuring $57mm{\times}50mm{\times}22mm$ in the right lobe of the thymus, and a well-encapsulated mass, measuring $32mm{\times}15mm{\times}14mm$ in the left lobe, were found. Both tumors were type B2 thymoma. Few cases of multiple thymoma with myasthenia gravis have ever been reported in the literature. We report a case of synchronous multiple thymoma associated with myasthenia gravis.

• Journal of Chest Surgery
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• v.45 no.4
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• pp.267-268
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• 2012

Thymoma is a common anterior mediastinal mass, although thymomas have occasionally been found in the neck, pulmonary hillus, or posterior mediastinum. But a thymoma within the middle mediastinum has rarely been reported. We report a thymoma arising in the middle mediastinum with a review of the literature.

• Journal of Chest Surgery
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• v.40 no.11
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• pp.759-764
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• 2007

Background: Thymoma occurs in approximately 10% of myasthnia gravis patients. The thymus or a thymoma plays a role in the pathogenesis of myasthenia gravis. However, there is currently no definitive position about the effect of thymectomy on patients' symptoms and prognosis. We retrospectively studied the effect of thymoma on re-mission in patients who underwent thymectomy for myasthenia gravis. Material and Method: From July, 1992 to December, 2002, we performed extended thymectomy due to myasthenia gravis for 100 patients. The thymoma group included 30 people, the non-thymoma group included 70 people and the change of the Ossermann stage between the two groups after surgery was compared. Result: For the non-thymoma group, the average age was 34.7 years (range: $12.7{\sim}47.7$). Before the surgical operation, the Ossermann stage for the non-thymoma group was an average of 3.00, and this was reduced to an average of 1.41 after operation. For the thymoma group, the average age was 50.9 years (range: $37.3{\sim}64.5$). Before the surgical operation, the Ossermann stage for the thymoma group was an average of 3.00, and this was reduced to an average of 1.47 after operation. The non-thymoma patients had a higher proportion of males than the thymoma patients (35% vs 30%, respectively), The Masaoka stage was stage of the thymoma group was I for 27 patients and stage II for 3 patients. There was no statistically significant Ossermann stage change between the thymoma and non-thymoma groups. Conclusion: Whether thymoma was present or not, there was no significant difference on remission and improvement of myasthenia symptoms after thymectomy in the myasthenia gravis patients.

• Tuberculosis and Respiratory Diseases
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• v.70 no.1
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• pp.74-78
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• 2011

Herein, we report a case of recurrent pleural metastasis after complete resection of invasive thymoma that was successfully treated with surgical resection. Thymoma and thymic carcinoma are uncommon neoplasms derived from the epithelial cells of the thymus. Approximately 30% to 50% of thymomas are asymptomatic at the time of diagnosis. However, these cancers may present with constitutional or local pressure symptoms and sometimes with paraneoplastic syndromes, especially myasthenia gravis. Surgical resection is the mainstay of thymoma treatment and has been shown to remarkably improve long-term survival. Despite complete resection, local recurrences are frequent, and surgery is the cornerstone of therapy even in cases of recurrent thymoma. We experienced a 67-year-old male patient with pleural metastasis that developed 6 years after complete surgical resection of invasive thymoma. The pleural mass was excised by video-assisted thoracoscopic surgery. Histopathological examination revealed an invasive World Health Organization (WHO) type B2 thymoma.

• The Korean Journal of Cytopathology
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• v.1 no.1
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• pp.36-42
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• 1990

The fluoroscopy-guided fine needle aspiration biopsy has been gaining widespread acceptance as a rapid and effective method to make a pre-operative diagnosis of mediastinal tumors including thymoma, malignant lymphoma, and metastatic carcinoma. Although thymoma is a most common tumor of the superior mediastinum, most cytopathologists are not experted in cytologic diagnosis of this tumor because of limited experience. In order to define the diagnostic cytologic features of thymoma, we have retrospectively reviewed imprinting smears and corresponding tissue sections from four cases of this tumor. All cases revealed an apparent biphasic pattern of epithelial cell clusters and lymphocytes with occasional branching capillary fronds extending from three dimensional epithelial cell clusters. Epithelial cell clusters predominated in one case and lymphocytes in two cases. Mixed epithelial cell and lymphocyte type represented in one of four cases. In the lymphocyte predominant type, the presence of epithelial cell clusters and small mature lymphocytes are helpful features to differentiate from a malignant lymphoma.